I have always loved Colorful Tabs. But the latest release for Firefox 57 was not tested enough. The tab bar appears mostly as a black blur, and you cannot even get to the "_" or the "X" at the top right of the window for minimizing and closing the browser. I hope there is some way to hear about an updated, functional release of this formerly great Firefox extension, because right now I have had to uninstall it. It just cannot be used in its most recent incarnation.